Valve mechanism



4 Sheets-Sheet 1 LNVENTOR Hu eri Lf/Pf' BY ATTORNEYS H, JEZLER VALVE MECHANLSM Filed Dec.

May 28,- 1935 @9.4mm 'wwa, ,www f aux..

l May 28, 1935. H. JEzLER i VALVE MECHANISM Filed Deo. lO, 1952 4 Sheets-Sheet 2 dfie/f 09m. /f M 6d* ATTORNEYS' May 28, 1935. l H. JEZLR Y A 2,003,001 v A VALVE MECHANISM' 'A 'j' f 0 Filed nec. 10, 1952 y4 shee'ts-sheet 5 v 4l Smets-sheet f4" H. .xr-:ZLERv VALVE MEHANISM Filed DC. l0, 1932 Patented May 28, Y1935 Y UNITED STATES- VVALVE MECHANISM' n Hubertl Jezler, Zurich, Switzerland Application` December 1o, 193.2',- serial No. 646,699 In Germany December 14, 1931 g n 9 Claims. *(Cl. 121-142) The invention relates to the variable control.

of the admission and exhaust of the voperative medium in two cycle piston engines. In such mechanism the control membersy continuously moving in the operative medium must. befas simple as possible, which is particularly essential at high temperatures of the operating medium. High admission pressures demand shorter admission periods and the tendency to utilize the.

10 entirey work of expansion in a single cylinder also requires a reduction of the admission period. The valvegear must operate asy accurately as possible for a-very early cut-off and must also be suitable for longperiods of admission. Very quick opening and closing motionsv as well as a good overlap `are necessary. The internal as well as external parts must be few in number and it is of paramount importance to reduce the Weight and speed of the reciprocating valve operating parts. A

According to the presentk invention these yconditions are satised in that the mechanism consists of a valve member having a passage `of fixed or invariable. area actuated from the driving shaft and a normally stationary or port member with a variable passage defining the opening controlled by the valve.

The valve member is preferably so arranged that it opens and closes the port both during its is driven at half the speed of rotation ofv the driving shaft. As van important feature .the

normallyr` stationaryY or portl member has 'the' ports formed'A between opposed edges which are simultaneously adjustable toward or from each other, symmetrically with respect Vto the mid position of the valve when Varying the passage section. Simultaneously with` this adjustment;

there is effected a variation of the angular position between the driving shaft and the control shaft. This interrelation may for example be such that the time point of opening-remains wholly and substantially unchanged. The member which determines the opening section may Vinclude two parts movable relatively/toward or away from each other. Y

forward stroke and during-its return stroke andV showingV my im gear mechanism withthe cut-off slides in partially open `position and illustrating diagrammatically in dotted lines the` cycles of thevalve gear motion and the crank motions forthe piston, v A Y Y Fig. 1b is a view similar to Fig. la., illustrating the position of, the parts vatthe moment of preadmiss'ionat shortadmissiorrr` Y l A Y I Fig. 1c. is a similar Viewat the moment' of cut-om. k

Figs, 1d and 1e are views corresponding toA Figs. 1b and lc and showing corresponding positions of the parts where a considerably longer period of admission is required,

Fig. 2V is a view similar toFig. 1, illustrating 15 amodified form ofthe invention, I

Fig. 3 is a View generally similar toFig. 1`v but illustrating a, typeof. construction using an oscillating valve,

Fig.- 3a is a sectionalview `the line 23a-3aV 20,'

ofFig.3. Y

In Figs.. 1 and la: is illustrated the 'drive of the valve from the driving shaft-by means of pairs `of gears having a driving` ratio of 2 to 1 ,with the.

interpositionof an adjustable coupling. The`25V setting -of the normally stationary member consisting of two parts for. determining the opening section (hereinafter referred to .asA the` chargeproducer) bymeans of control cams, In

additionthe adjustable coupling and the'controlr 30 Y camsare operatively connected by a common setting meansf. The illustration relates to thev control of the inlet of a single actinglcontinuous: current steam engine.y

The inlet member vconsists.,essentially 0`f135 tubuar valve I withthe inlet Vport 2 ofa width's, inv combination with the twopiston-like charge producers 3 and l3. `The port is interrupted by a single step, not shown in the drawings, for connecting together the two Valve halves.y The 40 valvel moves in the valve casing. 4 onwhich` the v,steam inlet pipe is indicated at'5 andthe supply passage to the working cylinder by f A6. The illustration is at the deadpoint of Vthe working piston 'I,`the charge producer 3,' 3 being V45 v closed in Fig. l and open for a certain chargeY Forms of Constmctions of the subject of the', 1n Fig. la. The controlling edges of the valveinvention are shown by way of example. inthe I I4, coupled together, and the toothedwheel pair I 5, I6., Byr theA toothed Wheeltransmission there 55 if Ywidth .of the port 2) is obtained a transmission of the engine revolutions to the control shaft revolutions in the ratio of 2:1. In the arrangement here shown the direction of rotation of the control shaft is anticlockwise when the driving shaft, looking in the same direction, rotates clockwise.

The charge producers 3,' 3' are connected by a hollow rod I'I and a rod I1 to the rollers I8, I 8' which run in guide slots I9, .I9'.- These slots arerigidly connected to the screw spindle 26 with which engages as a nut the bevel wheel 22 mounted in 2l. wheel 24 mounted on the control spindle V23. By turning the control spindle the guide vslots are moved at right angles to the valve axisandthus the two parts of the charge `producer are separated or drawn together. Y t y The coupling Ibetween the shafts I3andl4 is eifected by the sleeve 25' which at'one "end is connected tothe straight grooved portion of the shaft I3 and at the other end to the inclined grooved portionof the shaft 'I4 in the manner of a nut 25 and is mounted in the ring 26 which, serving as a nut, can be displaced byrneans of a thread 21 on the valve control spindle23.

The device describedthus permits of effecting,

simultaneously with theropening of the chargeV producer, a variation of the relative position ofthe driving crank and the control crank. In the position shown in Fig. l the two edges b and bof the charge producer are in'their middle position M and the centre'line of the valve port 2 (always assuming the dead point position of the working piston) also coincides accurately with M. The driving crank lies in the plane of the drawing, the control crank being at right angles thereto. Y n

"It willl be seen from Fig. 1a, that when the cut-off slides are opened by f, plus f', the slider` valve I (main crank at'dead center) must also be ,displaced from its center position by about f (the exact amount ofthisdisplacement depending upon therconditions required in regardV to pre-admission). Each opening of the charge producer corresponds'with a'denite turning of the` control crank yIl relatively to its direction of rotation from its positionat right angles tothe driving crank in the zero position. Y

For the directions of rotation indicated by the arrows 28, 29, 30 the upwardly directed control crank 0,' O1, at right angles to the plane of the paper Ain the zero position, must Ibe* turned through the angle O1, O, M away from its own direction of rotation.

For following the control operation attention is drawn to Fig. la.v In the position shown the Valve .will be seen during its movement towards the control crank corresponding withthe rota- 60. tion of the control crank in the direction of the full line arrow. The leadingedge a'has already passed the edgeb by the amount of the linear advance (which here is about equal'to half the The pre-admission tookv place whentheV edge' a coincided with b. Whilst the working piston moves from its dead pointV position at the cylinder head towards the crank an inflow occurs untilV the edge a of the valve closes with the edge b of the charge producer. This is the directly opposite position to the pre-` admission position as regards the mid-position O1. AfterV a path of calculated from M, the control crank has reached the position M' in vwhich the edges a and b' are relatively to one 22 engages with the bevel in the position shown, whilst the valve has moved away from the control crank. Meanwhile the driving crank has made a complete revolution of 360; the working piston is again in its dead point position at the cylinderl head and the cylinder receives during the return stroke of the valve its second charge, which is closed shortly after passing the position M".

On one stroke of the piston the admission opening is defined by the edges a( and b, and the closing of this admission port is by the edges a and b on the movement of the slide valve toward the control crank, whereas on the next lstroke of the piston the opening is effected by the edges a, and b and the closing by the edges va' and b as the main control valve travels away from its control crank.

In Figs. 1 and la as well as in Figs. 2, and 3a, the valve gear mechanism is shown in a position corresponding to a dead Vcenter position of the working piston. The moment of pre-admission is already passed and in the relative exhibition of the fixed and movable edges of the valve mechanism will be noticed the amount of the linear lead. Y

In Figs. 1b to le the example as based on Fig. l is shown as follows: Figs. lb and lc relate to a comparatively small period of admission. Fig. V1b illustrates the moment of pre-admission while Fig.- lc/shows the Ymoment of the cut-off. In Figs. ld and le the corresponding moments are illustrated for a considerably longer period of admission. 'I'he numbers and letters of reference inFigs. 1b to le are the same as used in Fig. l and in particular Fig. la. Special reference is made to the'designation M as used in Fig. la (for the position of the valve crank pin in dead center position of the working piston) and M* (for the symmetric position of the valve crank pin shortly before the cut-off).

The designations M and M* referring to the second half of a revolution of the valve crank pin have lbeen left off in'these ngures.

P designatesthe position of the valve crank vpin in the moment of pre-admission (Figs. 1b and steam passage when passing the fixed edge b of the cut-off slide 3. The valve Vcrank pin P is yet in a position advanced in relation to M by theamount of the angle MOP coordinated to the dead center of the working crank.

The angle MOP corresponds to the polar preadmission, which appears in the illustration of the working crank as angle TSK. Since the valve crank pin rotates at half speed of the working crank, the angle MOP is equal 1/2 of the angle TSK. The Valve crank pin P now vfollows a path over M, the absolute dead center O1 and Mi" symmetric to M until position 'P as indicated in Figs. 1c and le is reached. This is. the moment of cut-off, i. e. the position in which the edge a of valve I in cooperation with edge b ofthe cut-off slide 3' closes the steam passage. The working crank has correspondingly reached position K as indicated in Figs. 1c and 1e. The angular path of P from position as shown in Figs. 1b, 1d, respectively, to position as shown in Figs. 1c, 1e, respectively is one-half o'fthe corresponding :angular path ofK. The angles lOrOM indicate `the Vangle :of torsion 3by which the valve crank is-moved out of the center position O01 perpendicular tothe working crank if `the cut-01T slideV isV moved lby .an 'amount j.`V

This torsion in case 1d and le is .larger than in case .1b-and 1c because the/displacement is also assumed larger. .Especially the Vfreedom of choice for the inclination Aand form :of thelvalve control curves I9, I-9 (Fig. 1) "permits fthe designer to choose relations between lthe displacement f and the langle of torsion v@10M such, that with respect tol pre-admission la desired positive law (forexamplealso a constant polar `pre-admission) will be followed. YOnce the relations between position M and T are corare obtained. Of quite particular importanceV is the circumstancelthat in the steam space=only the light and simple tubular valve I ismoved, Whereas 'the charge producers 3, 3'., adjustable for the purpose of..varying the charge, depend on the operation of .the engine. The reciprocatin'gpartsare restricted to -the valve, including the valve rod Aand .the portion of thedvalvc thrust rod. The guide slots I9 also depend yon the operation of the engine; they can be made extremely precise and at the same time strong. The adjustable coupling I3, I4, 2B only .h'as'to transmit control forces; it may 'therefore also be constructed extremely precise' and robust and in addition is not subjected to any forces which change their direction. All the remaining control members are of the simplest kind imaginable.

By .this mechanism it is possible as regards pre-admission to effect a predetermined'course extremely accurately dependently on .the charge degree. Particularly it is also possible (with a restriction in the direct vicinity of'the lzeroy charge which can practically hardly be "observed) to obtain an accurately constant 'preadmission for the whole range. VFor .forward and `reverse drive it is possible to vproduce A.complete symmetrical ratios. The .rangeof control is unlimited andthe requirement of a very high maximum .charge does :notwin .anyway influence the leiciency and accuracy. of the control in the case of very small charges.

Figs. 2, 3, and 3a show other examples of construction of the subject of the invention. In these gures the Yparts yalready shown sin Figs. l and la are indicated by the same refer' ences and are only again explained Vin 'so 'far this is necessary in the other form of construction.

Fig. 2 shows an example oit-he lcontrol with a slide valve, adjustment `of .the Acharge :producer by means of left'and Vright hand screws and vturning between driving ycrankand -control crank by means of movable worm wheels. rrThe charge lproducer in this case consists of two parts, 3, 3 constructed in the manner of a slide valve which are connected by a rod I'I pre-'admission con--Y toothed wheel 44 there engages constantly thel pinion 46 of which the shaft 52, :mountedin 41, carries the toothed wheel 48 which through the intermediate wheel 49 gears with thetoothedv wheel 50. yThis is mounted on the` shaft 5I on which the toothed wheel 45. is keyed for axial' movement. relatively to one another butr 'are freely rotatable relatively to one another. Thehub of the wheel 44 fis rotatable on the part 52a but is axially immovable; Part 53 is mounted as a nut onk the screwed portion 454 of shaft52'.

The transmission of the movement from the driving shaft to the control shaft 3| in vthe proportion 2:1 iseiected by Va skew wheel Vpair .55, 56, the latter being .connected to the control shaft 3=I in an axially movable manner by ar key andfgroove. The bell crankl lever 5'I is connected at one end Vby a fork and pin to the hub of thewheel 55 and at the other lend to vavnut `26 on the screwed `portion 2'I ofVV the control spindle.

By turning' the control'y spindle `a rotation yin f opposite directions is ,produced Vbetween the driving crank .and thecontrol crank; simultaneously iorgexample 44 comes, into .engagement with 42 whereby the opening 'of the vcharge producer takes place.V In this manner there is for example set the forward movement from 0 charge to maximum charge.

vIn order to set for reverseV ,movement the control` spindle is turned from the middle position vshown in the opposite4 direction whereby a turning also takes place-inthe opposite ldirection between the driving crank and the control crank. Now however the toothed wheel comes into engagement with 42 so rthat in spite of Ithe turning of the control spindle in the opposite direction the toothed wheel 42 .-is turned inthe same direction as in the first case and thus the Acharge producer is opened as Vbefore. Y

.According to the selection of the pre-admision an interruption can be provided lbetween the change :of engagement ofV 44 and 45fwith 42 by dimensionin'g thepdistance between 44 and 45 so that on changing'from forward drive to reverse a turning of the control crankrelatively to the driving crank and thus a movement of the valve relatively to the closed charge producer, stationary in the mid-position, is possible.

Fig. 3 shows an example of construction* with oscillating; valve. The two parts 3, 3 of the chargev producerare also constructed in the,

manner of an oscillatory valve. Their axesV of rotation IT and il" are respectively connected to the bevel4 wheels ABI, 68. The Vlatter is;rig idly connected to the control spindle 23 and the former is connected thereto Yby means ofv the intermediate wheel V62. The transmission omovement lfrom the driving shaft Vtothe lcon.-

trol shaft 3|v is effected inthe .proportion` 2'2'1V by the spur wheels 63, 54. The latter is seated on an inclined grooved bush 65 which is con- 44 .and 45 are V,immovablev axiallyf nected in an axially movable manner/to the control shaft 3l by a key and groove. The lever 61, pivotally mounted atG, is connected by a fork and pin to the bush 65 and to the nut 26 engaging with the screw portion 21- of the controlspindle. The valve receives its oscillating movement by means of the hollow shaft ll, the crank 68, the eccentric rod 69 and the eccentric 'l0 from the control shaft 3|.

. In this ,example a reversal has not been considered.

What I claim is:

1. The combination with a single acting reciprocating engine having a pistonand a crank shaft, of a motive fluid control mechanism including a valvehaving a passage of invariable size for the motive fluid, means for imparting to said valve a back and'forth movement with Vone stroke for each two strokes of the engine piston,

aA pair of normally stationary members coactin'g with said valve to control the flow of motive fluid through said passage, means for varying the time of the stroke of theV valve in respect to that of the piston, and meansv for simultaneously ternately to uncover and cover said port during each stroke of said valve, means for imparting a back and forth movement to said valve with one stroke during each two strokes of the engine piston, means for varying the time of the stroke of the valve in respect to that of the piston, and means for Vadjusting said members toward or from each other Vto retard the time of closing said port while maintaining substantially constant the time of opening thereof.

3. The combination with a single acting reciprocating engine, having a piston and a crank shaft, of a control mechanism including a valve, a crank for operating said valve,v means for rotating said crank at onehalf the angular velocity of the engine crank shaft, said valvel having a port of fixed and predetermined size for the motive fluid, means defining a motive fluid passage for registry with said port, and

means for simultaneously adjusting the angular position of said crank in respect to the engine crank, and widening or narrowing said passage.

4. The combination with a single acting reciprocating engine having a piston and Va crank shaft, of a control mechanism including a valve, a crank for operating said valve, means for rotating said crank at one half the angular velocity of the engine crank shaft, said valve having a port of fixed and predetermined size for the motive fluid, means for adjusting the angular position of said crank inrespect to theengine crank, a pair of normally stationary members acting alternately to uncover and cover said port during movementy of saidvalve in each stroke, and means for moving said members toward or from each other upon change in the relative angular positions of said crank andthe engine crank shaft.

5. The combination lwith a reciprocating engine having a piston and. a crank shaft, of a control mechanism including a valve, a crank for operating the same, two to one gearing for driving the crank from the crank shaft of the engine to give to the valve'a back and forth movement with one stroke for each two piston strokes, an adjusting coupling for varying the angular position of said crank in respect to the engine crank shaft, said valve having a port of fixed and predetermined cross-sectional area for the motive fluid, a valve casing for said valve, and means in said casing for maintaining substantially constant the time at which said port is opened kfor all relative angular positions of said crank and the crank shaft.

6. The combination with a reciprocating engine having a piston and a crank shaft, of a control mechanism including a valve having a port of fixed and predetermined area, a valve casing having a passage of variable width with` which said port registers once during each stroke of the valve, means for imparting to said valve a back and forth movement with one stroke for each two strokes of the engine piston, means for varying the relative positions of the piston and valve in their respective strokes, and means for varying the width of said passage in accordance withvariations in the relative positions of the valve and piston in their strokes.

V'7. The combination with'a reciprocating engine having a piston and a crank shaft, of a control mechanism including a valve having a port of Yfixed and predetermined cross-sectional area, a pair of members normally stationary but adjustable toward and from .each other to form a passage registering with said port once during each stroke of said valve, means for imparting to said valve a back and forth movement with one stroke for each two strokes of the engine piston, means for advancing or retarding the valve'in respect to the piston, and means for automatically and simultaneously moving said members toward or from each other to vary the width of said passage.

8. The combination with a reciprocating engine having a piston and a crank shaft, of a control mechanism including a valve having a port of fixed and predetermined cross-sectional area, means for imparting to said valve a back and forthY movement, a pair of members normally stationary and movable in opposite directions toward and from mid-position of the valve, said members having edges coacting with said port to effect opening and closing of the latter, means for varying the position of the valve in its stroke in respectto the position of the piston, and means for simultaneously and automatically moving said members toward or from each other.

9. The combination with a lsingle acting reciprocating engine having a piston and a crank shaft, of a control mechanism including a valve having a port of fixed and predetermined area, means for imparting to said valve a back and forth movement, a pair of members normally stationary but movable in opposite directions toward and from 'the mid-position of said port, said members having edges coacting with said port to open and closev the latter once during each stroke of the valve, a control member,

means actuated by said control member for' varying'the position of the valve in its stroke in respect to the position of the piston, and means also operated by said control member for adjusting said members toward and from each other.

HUBERT JEZLER. 

